in a cos i change enable call duration limit on external calls to yes
and enable call duration limit on internal calls to no
in mitel phone it is work correct
its mean that in external call timer in enable but it is no action on internal calls
but we have some sip phone (atcom and yealink) and the timer block the internal calls on these sets
it is seem that all call duration of sip phone are external for mitel and can not detect of defrence of sip user and sip trunk
i hope it has a way to solve it